The Characteristics and Formation of Meanders

Meanders are sinuous flex in a rivers middle and lower courses. In low melt conditions, alternating pools and riffles are make along the river bed. The river channel is deeper in pools so it has greater energy and more erosive power. Energy is lost as the river leans over a riffle because of friction. These cause the rivers flow to become nettlesome and maximum flow to be concentrated on one expression of the river, causing lateral erosion on one side, creating an outer pouchlike bank.Deposition takes place on the other side of the bend, creating a convex bank. The crosswise of a meander is asymmetrical. The outer bank forms a river cliff or a bluff with a deep pool close to the bank, mainly because of the fast flow, hydraulic action and abrasion. The inner bank is a mildly sloping deposit of sand and gravel, called a point bar. Meanders are keep by a surface flow of water across to the biconcave outer bank with a balancing subsurface return flow back to the convex inner b ank.This corkscrew-like movement of water is called helicoidal flow. In this way, gnaw at material from the outer bank is transported away and deposited on the inner bank. The gang of erosion and deposition exaggerates the bends until large meanders are formed. Sometimes, oxbow lakes are formed when the neck of the loop of a meander is broken through, and the new blow eventually becomes the main channel, leaving the formed channel sealed arrive at by deposition.